Thermal switch



April 18, 1950 ALGER 2,504,370

THERMAL SWITCH Filed June 1, 1948 INVENTOR BY W.

ATTORNEYS.

Patented Apr. 18, 1950 THERMAL SWITCH John T. Alger, Portland, reg., assignor, by mesne assignments, to Frank Meyers and R. M. Spencer, both of Portland, Oreg.

Application June 1, 1948, Serial No. 30,229

1 Claim.

This invention relates to improvements in fire warning systems.

An object of the invention is to provide an improved temperature controlled fire warning system.

Another object of the invention is to provide an improved variably adjustable temperature controlled fire warning system.

A further object of the invention is to provide an improved variably adjustable switch actuator and fire warning system.

A still further object of the invention is to provide an improved fire warning system which will be highly efficient in operation, and relatively inexpensive to manufacture and produce.

Other objects will appear as the description proceeds.

In the accompanyin drawings which form a part of this application:

Figure 1 is a front elevation of the improved fire warning system including a, visual and audible signal means and actuating means therefor.

Fig. 2 is an edge view of the improved fire warning signal device.

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3.

Like characters of reference are used throughout the following specification and the accompanying drawings to designate corresponding parts.

In carrying out the invention, there is shown and provided an improved fire warning system including a cylindrical casing or housing i having a plurality of apertures 2 formed in spaced circumferential arrangement through it to permit air to pass readily into the interior of the easing or housing I for actuating a thermostatically controlled switch hereinafter more fully described.

A dial plate 3 will be supported in fixed position in said casing or housing I, and will bear a circularly disposed calibrated scale 4 on its outer surface. A glass disc 35 will be disposed in front of the dial plate 3 in the usual manner.

The casing or housing 9 will be provided with a solid back 5 formed with a forwardly directed securing flange 6 for sliding over the rear end of said casing or housing i. The front of the casing or housing I will be provided with a cylindrical rim 1 which is of right angular shape in cross section. The outer wall 8 of the cylindrical rim 1 is provided with a calibrated scale 9 for cooperation with a selectively set pointer it! formed on the arcuate slide plate H slidably disposed in the arcuate slot I2 formed through the wall of the casing or housing said slide plate II being provided with a radially and outwardly extending setting stud or handle is which will be grasped by a persons fingers when setting the pointer 10 to the desired temperature calibration 9 upon the outer wall 8 of the cylindrical front rim 1. The slide plate H will be preferably made from any desired insulating material which is a non-conductor of electricity, and will support the inwardly directed L-shape switch contact supporting arms i l and M having contacts 48 and thereon. Screws it will secure the contact arms [4 and is to the slide plate It and will also secure the electric conductors H and I8 which will be connected in series with a visual light signal i9 and audible buzzer signal 20, and to a source of electric current supply (not shown) Bearing plates 2! and 22 will be secured to the back 5 and to the inner surface of the dial plate 3 by means of the screws 23, and will support the bearing rod 24 therebetween.

A pointer 25 for cooperation with the scale indicia 4 upon the dial plate 3 will be mounted upon the stub pivot shaft 26 extending through and rotatably supported by the dial plate 3.

A series of coiled thermostat elements 21 capable of expansion and contraction are secured to their inner ends to collars 28 fixed upon the pivot shaft 26 and have their outer ends extending tangentially to be hooked at 29 about the bearing rod 24. A series of radially extending switch actuating arms 3i] will be supported by the collars 28 about the pivot shaft, and when the thermostat elements 27 expand due to heated air entering into the casing or housing i through the apertures 2, the arms 3G will engage the cross bar 3| secured to the switch arm M to force its contact 45 to make electrical contact with the contact 40 on the switch arm 14, thereby closing an electric contact including the thermostat controlled switch, the visual lamp signal I9, the audible buzzer signal 29, and the source of electric current supply (not shown).

It will be obvious that since the switch arms M and M are movably and adjustably supported upon the slide plate H, various desired settings may be made for causing the closing of the switch contacts and circuit controlled thereby at any desired temperature. Thus in case of a fire nearby the device, when the temperature rises to that set, will automatically actuate the switch and cause a visual and audible alarm.

Due to the fact that a series of thermostat elements 21 are provided and pivotally supported independently of each other, the heat entering the casing through the openings 2, will affect the outermost thermostat element, and as the heat builds up within the casing, the remaining thermostat elements will operate to further complete the circuit to the signal.

Should the heat become so great as to destroy the outermost thermostat element, the next thermostat element would operate to cause the signal, and should the heat become so great as to destroy the intermediate thermostat element, the innermost thermostat element would then operate to complete the circuit.

While the preferred embodiment of the instant invention has been illustrated and described, it will be understood that it is not intended to limit the scope of the invention thereto, as many minor changes in detail of constructionmay be resorted to without departure from the spirit of the invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

A thermostatically operated switch, comprising acasing having a closed back and a' dial plate closing the front, said casing having an opening in the side thereof, a post rising from the center of the casing, a slide plate mounted concentrically with the post, within the casing closing said opening in the casing, said casing having a, line of openings disposed adjacent to the back thereof, through which air passes into the casing, normally spaced switch arms extending inwardly from the slide plate, a cross bar secured to one of the arms adjacent to the end thereof, a series of thermostats mounted on the post within the casing arranged side by side in spaced relation with each other, between the line of openings and dial plate, the thermostats being successively further away from said line of open- 'ings, actuating arms formed integral with the thermostats, adapted to engage said cross arm, moving the switch arms into engagement with each other.

JOHN T. ALGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 578,345 Maxim Mar. 9, 1897 1,199,050 Cid Sept. 26, 1916 1,824,933 Scholtz Sept. 29, 1931 2,456,062 Iwanski Dec. 14, 1948 

